Which planet is most like Earth?

Which planet is most like Earth?

• A. Venus
• B. Mercury
• C. Mars
• D. Uranus

Answer: (A)

Think about what makes a planet similar to Earth: being rocky, and having a size and mass close to Earth’s, so the internal structure and gravity are not radically different. Among the options, Venus fits this best. It’s a terrestrial planet with a size and mass very close to Earth’s—its radius is about 95% of Earth’s and its mass around 80-85% of Earth’s—and it shares a similar rocky composition and interior. That makes Venus the closest match in these fundamentals, even though its atmosphere is extremely thick and hot, leading to very different surface conditions. Mercury is smaller, with a very different environment and a thin atmosphere; Mars is also smaller and thinner, with a different geology and weaker gravity. Uranus is a distant gas/ice giant with no solid surface, so its overall makeup is far from Earth’s. So Venus stands out as the planet most like Earth in overall structure and size.

Think about what makes a planet similar to Earth: being rocky, and having a size and mass close to Earth’s, so the internal structure and gravity are not radically different. Among the options, Venus fits this best. It’s a terrestrial planet with a size and mass very close to Earth’s—its radius is about 95% of Earth’s and its mass around 80-85% of Earth’s—and it shares a similar rocky composition and interior. That makes Venus the closest match in these fundamentals, even though its atmosphere is extremely thick and hot, leading to very different surface conditions.

Mercury is smaller, with a very different environment and a thin atmosphere; Mars is also smaller and thinner, with a different geology and weaker gravity. Uranus is a distant gas/ice giant with no solid surface, so its overall makeup is far from Earth’s. So Venus stands out as the planet most like Earth in overall structure and size.